Of buns and bread

On my way home, I went to the vending machine at the lobby of my condo to buy a bun (for my dog). I inserted the coins in, punched the buttons for my selection, and watched the bread get pushed out and fall down onto the collection tray.

While keeping my coin pouch, I wondered to myself, "What if I forget to collect my bread after I keep my coin pouch?"

Then I inserted my hand into the collection tray and saw my bun - and an extra loaf of bread. Evidently, someone had purchased the bread but forgot to collect it.